Dyestuffs



Patented Nov. 27, 1951 UNTTED STATES J v 2576,2932 1 Y n nY sTU'F'i s iI Harold France and Norman H ultoil xHadddok} Bla'ckley, Manchester,England, assigxiors' 16" Imperial Chemical Industries'i'Limited cw 'oor-Y poration of Great Britain 4Claims. (01. still-531416).

inve'xrtrcrr relates to newcyestum and more particularly to new wooldyestufisof the xanthene series which are capable of being chromed. 7

In British Specification No. 472,757 it was proposed to manufacturedyestuffs of the xanthene series capable of being chromed by condensing1 molecular proportion of3- or '-hydroxytrimellitic acid or anhydridewith 2 molecular proportions of am N-substituted m aminophenol, forexample 3-hydroxydiphenylan'1i'ne and to convert the products intosulphonic acids by treatment with sulphonating agents. The lightfa'stness of such dyestuffs is enhanced by chroming and some sulphonateddyestufis of this kind after being chromed have alight fastfiss as highas 4-5 on the Society of :Dyersi aI-fid'z Colouris'ts scale.

We have now found that if as N-substituted m-aminophen'ol's thereare-used 3-'-hydroxy-2' :6- dimethyldiphenylaminestor condensing with 5-hydroxytrimellitic acid or anhydride there are obtained on sulphonating,dyestufis which on chroming: give. bright-red. shades of light fastnessof about '7 on the Society of Dyersand Golourists scale. Such a light fastnessl-is-unii'siially high for a d'yestufi of the xanthene series.

According to our invention therefore weprovide a process for themanufacture of new dyestuffs which comprises treating 3:6-di-(226-dimethylanilino) -4-hydroxy -5'-carboxy-fluoran and/or 3 6-di- (2:G-dimethylanilino) -5'-hydroxy- 4'-carboxy-fiuoran with a sulphonatingagent.

The new dyestuffs in the form of their free acids thus have theformulae:

I or the corresponding tautome ri c quiiionoid forsolution.

me e: c -z e ehenisae q-ts u -oi pmbably attached to' thedimethylanilino nucleus; I The sulphonation may be carried out'bytreating the find-ra n derivative with for example sulphuric-acid andthe new dyestuff may be isolatedifor example by pouring theisulphonation mixturein'towater and filtering. The fiuora n derivative used asstarting mate:- rial may be made fore'xairi'ple by (1) reacting afizff-dimethylaniline, for example m-Z-Xylidine with m-chlorophenoL or,r'esorcinol and condensiing 2 molecular proportions of the 3-hydroxy;2':6'4dimethyldiphenylamin so obtained with 1 molecular proportion of5-=hydroxytrimellitic acid to form the 3:6-di-(2z-6-dimethylanilino) -4hydroxy-5-carboxy-fiuoran and/or the isomeric 3 z-d-di (216 w*dim'ethyl'anilino') ,-=5 hyd-roxyi 9.4 carboxy fiuoram o'r =t2lbyrea'cting- 5-hydroxytri meil-i-tic acid withs2- molecular proportionsof m- ,ch-lorop-l'ienol and condensing theresulting 3 :6 dichloro l on5-hydroxy- 5"- or 4,-carboxyfluoran. with 2' molecular, proportions ofthe 2 :'6'

dimethylaniline, or (3} by reacting s-uyarsry 11.3 parts ofB-hydroxytrimellitic acid and 10.65 parts of3-hydroxy-2:6-dimethyldiphenylamine are heated together at C. and 6.6parts of anhydrous zinc chloride are added. The mixture is heated to C.and stirred at 178-182 C. for 3%; hours. The viscous green iridescentdark red mixture so obtained is then cooled, powdered and added to amixture of 500 parts of water and 10 parts of concentrated hydrochloricacid. The mixture is stirred and heated slowly to 80 C. and stirred at80-85" C. for 15 minutes. The red dyestufi is filtered ofi, extractedagain with dilute hydrochloric acid, filtered ofi, washed with wateruntil free from mineral acid and dried.

5.1 parts of the above dyestufi are added during 45 minutes to 50 partsof 100% sulphuric acid at 10-12 C. and the solution is stirred at thistemperature for a further 1 hour when a test portion of the solution iswholly soluble in aqueous sodium acetate solution. The sulphonationmixture is then poured onto 250 parts of crushed ice and theprecipitated red dyestufi is filtered off and washed with 60 parts of15% salt The dyestufi thus obtained may be purified by dissolving it in250 parts of water at and then adding 30 parts of salt. The precipi-Jtated dyestufi is filtered off, washed with 60 parts of 15% saltsolution and dried to a bright red powder. The new dyestuff when appliedto wool and chromed gives a bright red shade of light fastness of '7 onthe Society of Dyers and Colourists scale.

A similar dyestufi may,a1so be obtained by using, in place of the 50parts of 100% sulphuric acid at 10-12" C. for 1 hour, 100 parts of94-96% sulphuric acid at 55-65 C. for 1 hour, or 100 parts of 90%sulphuric acid at95-100 C. for 1 hour. Weclaim: I I

1. The new dyestufls which are represented by the formula- CH. CH;

NE NH where one of the substituents marked X is a.

hydroxyl group and the other is a carboxyl group.

2. Process for the manufacture of new dyestuffs which comprises treatinamember selected from the group consisting of-3:6-di-(2:6-dimethylaniline) -4'-hydroxy-5 -carboxy-fluoran and 3 6-di(2:6 dimethylanilino) 5' hydroxy 4' carboxy-fluoran with asulphonating agent.

4, 3. The dyestuff which is represented by the formula- (3H3 on. Q C

Hi l

oon

4. The dyestufl: which is represented by the formulw- F CH3 OH! H 0 Q NE--SO;H

Name Date Eckert Sept. 15, 1942 Number

1. THE NEW DYESTUFFS WHICH ARE REPRESENTED BY THE FORMULA-